I have a Alpine CDA-9811 head unit that worked great until I put it in my friends car for a test. It worked in there, but now I have no output from the speakers in my system. This is from the amplifier that is built into the unit.

I checked the menu and the ams are turned on, I have it on the bench right now to check but do not know were to start looking for the problem.

None of the outputs are working and the heatsink on the back of the unit gets warm (not hot) which makes me think that the amplifiers may be working but in somekind of a mute mode?

Are there internal fuses in this head unit that I can check? I did reset the system. Could there be an issue with the face plate that is causing this? I assume that it is working correctly because it beeps when I go into the setup mode, but, the tuner up and down buttons seem to be acting up (the tuning does not move when I press them)

I cannot afford to buy a new head for my car and this should be an easy fix, but I cannot seem to find schematics on it (less buying from e-bull)

If you have a volt meter, set it to the DC volts selection and check from ground to each speaker wire, one at a time of course. You should have about 6 volts on each of the 8 wires. If you have 10 volts on one wire and a volt or 2 on the other 7 wires, you have a bad output chip.

Yes that pretty much rules out the chip itself. Go back through the menu and make sure the AMP-IC function is still on. 9815 is AMP-IC, it might have a different name on the 11. Also if the switch on the bottom got switched you may have to unplug the harness or reset the radio.
If none of that works, do you have any way to check the RCA outputs? headphones and a stripped Patch cord? a jam box with AUX input?

Thanks!
The amp is set to on, I have tried the ai-net switch both ways, reseting the unit each time. I have it running on a modified PC power supply so I can kill the power at any time. I just hooked it up to a old pioneer stereo that i have down here and there is nothing coming out of the front or rear pre-outs.